Load-balancing distributed raster image processing

A method of operating a printer having an on-board renderer and a marking engine, the method comprising:

• accepting a print stream comprising at least one page in PDL format and one page in raster format;
• parsing the print stream and sending those print stream pages in PDL format to the renderer for rasterization;
• and
• submitting rasterized pages from the renderer, and print stream pages that arrive at the printer in raster format, to the marking engine in an order such that pages rasterized on-board the printer are interleaved in their proper print order with pages arriving at the printer in raster format.

A print device comprising:

• a marking engine;
• a renderer capable of rasterizing PDL-format pages;
• an interpreter capable of parsing a print stream comprising at least one page in PDL format and at least one page in raster format, and passing PDL-format pages to the renderer and raster-format pages to the marking engine;
• and
• a scheduler to interleave raster-format pages from the renderer with raster-format pages from the interpreter such that raster-format pages are received by the marking engine in proper print order.

A RIP server comprising:

• a buffer to receive print stream data from print clients;
• a renderer to translate PDL-format page data to raster-format page data;
• a spooler having print stream inputs connectable to the buffer output and the renderer output, and print stream outputs connectable to the renderer input and server output, the spooler capable of routing at least one PDL-format page from the buffered print stream through the renderer before placing that page at the server output;
• and
• a page-processing selector to select a subset of the pages in a mixed raster/PDL render-format print stream for routing by the spooler through the renderer.

A load-balancing print driver comprising:

• a first rendering module to render pages in PDL format;
• a second rendering module to render pages in raster format;
• an encapsulation module to interleave pages from the first rendering module and second rendering module in a common print stream, the encapsulation module having the capability to add job control language commands between pages accepted from different rendering modules to demarcate render format boundaries;
• and
• a selection module to select which pages in a print stream to render with which rendering module.

An apparatus comprising a computer-readable medium containing computer instructions that, when executed or interpreted by a processor, cause the processor to perform a method of print processing, the method comprising:

• extracting data representing a first subset of pages from a print stream comprising data for multiple successive pages;
• rasterizing the extracted data;
• inserting the rasterized data in the print stream to represent the subset of pages;
• and
• passing the print stream towards a printer marking engine.